Tom Gardner (nospam) wrote:
What's the secret? I have a Whall clipper to do the Schnauzers and the
blades are about $20 new so, I figured I could surface grind them. I jigged
them up and took about .010" off top mating surfaces and I thought I did a
good job but they don't cut at all and I can't see why not. The look like
they should! Am I missing something? Are they magic?

Tom,
Re-read Bam's reply to your question about sharpening clipper
blades. What he said is correct!

I have a sharpening business, and although I don't do clipper
blades myself, I do know how they are done, using horizontal flat
honing/sharpening machines.

They are sharpenened on a horizontal spinning, flat-appearing
plate, which has an abrasive mixture of grit and lard oil applied to
the plate. The blade(s) are held such that the teeth are oriented
radially.

The sharpening plate is ever-so-slightly domed, meaning that it is
slightly higher in the center, compared to out at the periphery. The
difference in height between the center and the peripehery varies,
depending on who manufactured the plate, and what type blades are to be
sharpened on that particular plate.

So, if you lay a straightedge radially on the plate, you should
see that the plate is flat, but the straightedge isn't quite
horizontal. It's higher near the center of the plate. Hence the dome
shape of the plate. It helps if you visualize a dome-shaped plate, but
one which is tall rather than flat, and you imagine applying a flat
blade to the dome, you'll see how the blade ends up with a hollow
grind.

The reason for the dome shape is to produce a hollow grind on the
blade surface being sharpened. Most clipper blades are sharpened with
this hollow grind. And you might be interested to know that all
scissors also have a hollow grind. If you open up any scissors and
examine the inside of the blades (the surfaces facing each other when
the scissors is closed), you'll see this hollow grind. This hollow
allows the two blades to cut together, and also maked the edges a bit
thinner/sharper.

What I have described is how blade manufacturers sharpen new
blades, as well as any knowledgeable sharpener. And each time a blade
is sharpened, you only remove perhaps a few thousands. So, if you
removed the hollow when you sharpened the blades, they probably won't
cut.

I would also add that often even perfectly sharpened blades won't
cut, due to problems with the clipper malfunctioning, or being
improperly set up or misadjusted.